Dishwasher water circulation mechanism



y 1967 M. E. ULLMAN, JR.. ET AL 3,319,651

DISHWASHER WATER CIRCULATING MECHANISM Filed Dec. 10, 1963 3Sheets-Sheet 1 i L i '1 "f u U, E M 262 266 F 5a )1 2 Q INVENTORS.

MYRON E, ULLMAN, JR. gu JERRY M. HARROFF May 16, 1967 M. E. ULLMAN. JR.ET AL 3,319,651

DISHWASHER WATER CIRCULATING MECHANISM 2 m .F M ah m NN R e M 5 AR MA Rw u & s 5 MW g 3 N9 om N8 mvm 9w ma Y f Man Filed Dec. 10, 1963 May 16,1967 5 ULLMAN, JR, ET AL 3,319,651

DISHWASHER WATER CIRCULATING MECHANISM 3 Sheets-Sheet 5 Filed Dec. 10,1963 INVENTORS. MYRON E.ULLMAN JR. 8 JERRY M.HAR

United States Patent Ofifice 3,319,55i Patented May 16, 1967 3,319,651DISHWASHER WATER CIRCULATION MECHANISM Myron E. Ullman, Jr., Canfield,and Jerry M. Harrolf,

Salem, Ohio, assignors to Mullins Manufacturing Corporation, Salem,Ohio, a corporation of Ohio Filed Dec. 10, 1963, Ser. No. 329,422

13 Claims. (Cl. 137563) This invention pertains to the art ofdishwashers and more particularly to a mechanism for circulating waterin a dishwasher to accomplish the washing, rinsing and draining cyclesby a single mechanism.

The inventory is particularly adapted for circulating washing andrinsing water in a jet tower type of domestic wishwasher and it will bedescribed with particular reference thereto; however, it will beappreciated that the invention has much broader applications and may beused for other domestic and institutional dishwashers and otheranalogous washing units.

A domestic dishwasher generally includes a cabinet for receiving dishesto be washed, a spray system for impinging water onto the dishes and twodistinct water circulating mechanisms. The first mechanism is used tocirculate water through the dishwasher cabinet during the washing andrinsing cycles and the second mechanism is used to drain the spent waterfrom the cabinet between these cycles. In the past, these watercirculating mechanisms for domestic dishwashers included a complex ofvalves, solenoids to actuate the valves, motors, pumps driven by themotors, and a complicated housing for enclosing these many elements. Dueto the extreme complexity of the water circulating mechanisms heretoforeused in domestic dishwashers, they have been quite expensive tomanufacture and have been the most common source of failure during useof the dishwasher.

The present invention is directed toward an improved Water circulatingmechanism for a domestic dishwasher which substantially reduces theinitial expense of manufacturing the dishwasher and decreases theprobability of mechanical failure of the dishwasher during use. Inaddition, a dishwasher recirculating mechanism constructed in accordancewith the present invention can be easily repaired in the home withoutrequiring special mechanical skills or tools.

In accordance with the present invention, there is provided animprovement in a dishwasher water circulating mechanism comprising acabinet having a lower sump, a recycling passageway communicated withthe sump, a drain passageway, a valve means for selectively connectingthe drain passageway with the sump, impeller means in the recyclingpassageway for pumping water from the recycling passageway into thecabinet, and impeller means in the drain passageway for exhausting waterfrom the sump when the valve means is opened. The improvement of themechanism as defined above as contemplated by the present inventioncomprises the provision of the recycling passageway directly below thesump and the drain passageway directly below the recycling passageway.The valve means for connecting the drain passageway With the sump ispositioned between the two passageways so =that water will flow from thesump into the recycling passage-way when the valve is closed and, whenthe valve is opened, water will flow from the sump through the recyclingpassageway and into the drain passageway where it can be exhausted bythe drain impeller.

In accordance with another aspect of the present invention, there isprovided, in a dishwasher water circulating mechanism as set forthabove, a further improvement which includes mounting the recyclingimpeller coaxially with respect to the drain impeller and coupling bothof these impellers to a single output shaft of one, non-reversibleelectric motor. In accordance with the preferred embodiment of thepresent invention, the common axis of the impellers is vertical and themotor is mounted above the recycling impeller so that water will notdrain from the passageways into the interior of the motor, in the eventof seal failure.

In accordance with still a further aspect of the present invention, adishwasher water circulating mechanism as defined above is providedwhich includes a single housing, a single, nonreversible electric motorfor driving the recycling impeller and the drain impeller and a single,externally actuated valve for controlling the operation of thecirculating mechanism. This substantially reduces a complexity of thewater circulating mechanism in a manner which will be hereinafterdescribed in detail.

The primary object of the present invention is the provision of adishwasher water circulating mechanism which is economical tomanufacture, easy to install in a dishwasher and durable in use.

Another object of the present invention is the provision of a dishwasherwater circulating mechanism which includes a single, non-reversibleelectric motor with the dual function of recycling the water through thedishwasher during the washing and rinsing cycles and, also, draining thewater from the dishwasher between these cycles.

Still a further object of the present invention is the provision of adishwasher water circulating mechanism which includes only one easilyactuated valve for chang ing from the water recycling stage of themechanism to the water exhaust or drain stage of the mechanism.

Yet another object of the present invention is the provision of adishwasher Water circulating mechanism which includes a single housing,a single drive motor and a single externally actuated valve thatperforms all of the functions of the heretofore more complex w-atercirculating mechanisms for dishwashers.

These and other objects and advantages will become apparent from thefollowing description used to illushate the preferred embodiment of thepresent invention as read in connection with the accompanying drawingsin which:

FIGURE 1 is a partially cross-sectioned, side elevational view of adishwasher having a water circulating mechanism constructed inaccordance with the preferred embodiment of the present invention;

FIGURE 2 is an enlarged, cross-sectional side view illustrating thepreferred embodiment of the present invention;

FIGURE 3 is a cross sectional view taken generally along line 33 ofFIGURE 2; and

FIGURE 4 is a partially cross-sectioned view taken along line 4-4 ofFIGURE 3.

Referring now to the drawings wherein the showings are for the purposeof illustrating a preferred embodiment of the present invention only andnot for the purpose of limiting same, FIGURE 1 shows a domesticdishwasher A having a substantially watertight cabinet 10 with a frontaccess door 12, upper cover plate 14 and a truncated lower wall 16. Thecabinet may be supported by any of a variety of structures; however, inaccordance with the illustrated embodiment of the present invention, thecabinet i supported upon a lower mounting base 29. Dishes and otheritems to be washed are supported within the cabinet on movable racks 22,24.

Water is directed into the cabinet 10 through a water inlet pipe 30 uponactuation of valve 32 by an appropriate electrical signal from a sourcewhich is not shown. To prevent siphoning through inlet pipe 30, there isprovided an anti-back siphon chamber 34 which operates in accordancewith known principles. In spaced relation- 1 ship with respect to racks22, 24 there is positioned a perforated jet tower for impinging watersupplied through line 42 onto the dishes supported on racks 22, 24. Thiswater has an appropraite direction and velocity to clean all surfaces ofthe dishes. During the initial or washing cycle of the dishwasher, thewater contains a detergent or other cleaning substance while clear wateris used during the rinsing cycle. Water is exhausted from the cabinet 10through a drain line 44 connected onto a water circulating mechanismwhich mechanism forms the subject matter of the present invention.

This discussion of the structural details and function of dishwasher Ais for the purpose of explaining the environment to which the presentinvention is particularly adapted; however, it is appreciated thatvarious structural changes may be made within the dishwasher withoutaffecting the function and general construction of mechanism 50.Basically, the mechanism 50 circulates water from the truncated wall 16,through the perforated jet tower 40, into the interior of cabinet 10while the dishes are being washed or rinsed. Between these cycles, themechanism 50 exhausts the spent water from the cabinet 10 through thedrain line 44. The operation of mechanism 50 will be hereinafter setforth in detail.

A circulating. mechanism 50 constructed in accordance with the presentinvention may take a variety of structural forms; however, there isillustrated in the drawings a preferred embodiment of the inventionwhich has proven very satisfactory in use. The mechanism 50 includes asump 52 connected onto the lowermost end of truncated wall 16 and havinga generally funnel-shaped housing 54 with an upwardly facing shoulder 56and an outwardly protruding annular flange 58. The junction between thewall 16 and the housing 54 is sealed by an annular seal 60 having aninner lip 62 molded to encompass flange 58 and an outer lip 64. Tosecure the junction between the wall 16 and housing 54, there isprovided, in accordance with the illustrated embodiment of the presentinvention, a metal strap 66 of conventional construction. A pair ofmetal straps 68, similar to strap 66, are adapted to connect the sump 52onto the upper portion of mechanism 50 as is best seen in FIGURE 1. Theshoulder 56 supports a coarse mesh screen 70 which acts as a coarsefilter adjacent the lowermost portion of truncated wall 16. The screenmay be easily removed from the sump 52 for the purpose of cleaning.

Referring now to FIGURES 2 and 3, mechanism 50, constructed inaccordance with the present invention, includes a single housing havingan upper housing portion 82, a lower housing portion 84 and a centralpartition 86 which combine to define an upper recycling passageway 90and a lower drain passageway 92. These vertically spaced passageways aresomewhat coextensive within the housing 80.

Adjacent the end of passageway 90 opposite sump 52, there is provided arecycling pump having a housing 102 secured onto housing 80 by aplurality of spaced bolts 103. The housing 102 defines a pumping chamber104 having an axial pump inlet 106 and a tangentially extending pumpoutlet 108 for directing water from the pumping chamber 104 into thewater supply line 42 for ultimate use by the jet tower 40. The inlet 106is defined by an opening 110 in the upper wall of housing portion 82which opening receives a ring 112 having an upper inclined surface 114defining the lower portion of pumping chamber 104. Within the pumpingchamber there is provided an impeller having a plurality of spirallypositioned blades 122 with downwardly contoured surfaces substantiallymatching the inclined surface 114 of ring 112. The impeller 120 has anupwardly tapering, generally conical surface 123 which prevents theentrapment of air around the downwardly facing surface of impeller 120.This feature increases the efficiency of impeller 120.

Centrally positioned within the impeller 120 is a metal insert 124 whichthreadedly receives shaft 126 of a single,

non-reversible electric motor 128. The electric motor is mounted ontothe pump housing 102 by a plurality of circumferentially spaced mountingposts 129. At the upper end of housing 102 there is provided a shaftseal 130 comprising a stamped metal cap 132 which is forced into opening134 of pump housing 102 so that it will not rotate with respect thereto.Within the cap 132 there is provided a sealing boot 136 extendingbetween the cap and a graphite sealing ring 138 which is biaseddownwardly by a spring 140 against a ceramic sealing ring 142 securedwithin the impeller 120 and around the insert 124. To secure the ceramicring 142 with respect to the impeller, there is illustrated a resilientmaterial 144. To energize motor 128 there is provided a starting relaywhich is secured onto boss 152 of housing portion 82. The position ofthe relay 150 allows easy repair without dismantling the mechanism 50.

The recycling stage of the mechanism 50 can be appreciated from thestructure so far described. Water enters passageway 90 from sump 52where it is pumped by impeller 120 through outlet 10 8 into the supplyline 42 for reuse by the jet tower 40. The upwardly inclined surface 114of ring 112 provides a gradually decreasing area to maintain the desiredvelocity gradient through the pump. The motor 128 is positioned abovethe pump 100; therefore, there is no possibility of water leaking fromthe housing 102 into the interior of the motor 128.

Directly below the recycling pump 100 there is provided a drain pumphaving a pump housing 162 formed integrally with partition 86 as is bestshown in FIGURE 2. The housing 162 forms an internal pumping chamber 164having an axial inlet 166 communicated with the drain passageway 92 anda tangential facing outlet 168 communicated with the drain line 44.

In accordance with the illustrated embodiment of the present invention,the pump 160 has an impeller 170 with impeller blades 172. The impelleris best shown in FIG- URE 3. Although only two blades are illustrated,it is appreciated that the impeller may take a variety of structuralembodiments including more than two blades. The impeller 170 is drivenby a shaft 174 having an upwardly extending extension shaft 176 with across section adapted to match the cross section of opening 178 in post179 car-. ried by the metal insert 124. The coupling between shaft 176and opening 178 forms an axially slidable spline-like connection so thatthe vertical spacing between the im? pellers 120 and 170 is adjustableto accommodate various manufacturing tolerances in the housing 80.

Directly below the lowermost end of shaft 174 there is provided a boss180 integrally formed with respect to housing portion 84 and adapted toreceive a metal bearing insert 182 which determines the vertical spacingof ink peller 170 with respect to the pump housing 162. This insertextends above the top of boss 180 so that there is no radial restraintimposed upon shaft 174 by the lowermost connection of the shaft. Thisconstruction greatly facilitates assembly and decreases the detrimentaleffect of variations caused by manufacturing tolerances. The impeller120 is located within pump chamber 104 in a vertical position determinedby the threadable connection between insert 124 and shaft 126 as is bestshown in FIG- URE 2. Since the vertical positions of the two impellersare determined by the motor shaft and the insert 182, the slidabledriving connection between shaft 176 and opening 178 compensates forstacking of tolerances from the lowermost portion of housing 80 to theuppermost portion of the housing. This is a distinct advantage in theconstruction of the dual impeller water circulating mechanism.

T 0 seal the pump chamber 164 from the recycling passageway 90, there isprovided a seal having a generally annular cover 191 with appropriatelypositioned rein forcing ribs 192. Around the periphery of the cover 191there is provided an outer annular seal 194 for sealing the housing 162at the periphery of cover 191. A flexible molded shaft seal 196 isprovided with an outer lip 197 and a flexible boss 198 forming a largesealing surface with the shaft 174. The lip 197 is secured onto thecover 191 by an inner snap ring 199. The complete seal 190 is securedonto the partition 86 by a locking ring 200 with upwardly extendingfingers 202 adapted to bite into the surfaces of the partition toprovide a positive lock between the ring and the partition.

The advantages of providing two impellers driven by a single,non-reversible motor located vertically above the impellers have beenmentioned in connection with the description of the preferred structuralembodiment of the invention; however, it should be appreciated that theuse of a single motor which simultaneously drives the two impellerseliminates the need for two separate motors or one reversible motor. Inthe prior art when a single motor was used for recycling the water in adishwasher and for draining the water from a dishwasher, it was usuallynecessary to reverse the motor to accomplish this dual function. Such aconstruction was quite complex. This disadvantage has been completelyovercome by the present invention since both impellers are continuouslydriven in the same direction by a single, non-reversible motor and thetransition from the recycling stage to the drain stage is accomplishedby a single externally actuated valve which will be hereinafterdescribed in detail.

Referring again to FIGURE 2, the recycling passageway 90 is positioneddirectly above the drain passageway 92 and is generally coextensivetherewith. The direction of water flow from sump 52 is determined by theposition of a single valve 210 which controls communication between thevertically spaced passageways. Valve 210, in accordance with thepreferred embodiment of the present invention, is positioned withinopening 211 of partition 86 which opening is provided with a valve seat212 on the lowermost side of the partition and tapering outwardly fromthe uppermost side of the partition for a reason to be hereinafterexplained in detail. The valve 210 includes a valve body 214 having anupper integral shoulder 215 and a resiiient valve lip 216 clampedbetween shoulder 215 and a ring 218. The ring is held in position on thevalve body by a pin 220 extending between downwardly protruding lugs 222on the valve body 214.

-Valve 210 is actuated by an externally mounted actuator 230 comprising,in accordance with the preferred embodiment of the present invention, asolenoid 232 having a downwardly extending control arm or armature 233.The solenoid is provided with a mounting bracket 234 secured onto lug236 at the sump end of housing portion 82 as is best shown in FIGURES 2and 3. Extending in a generally horizontal direction there is provided avalve fulcrum rod 249 protruding into housing 80 through aperture 242 inhousing portion 34. The fulcrum operation of rod 240 is determined by aswivel or pivot seal 244 formed of a molded resilient material whichextends into a reduced portion 246 of fulcrum rod 240. To preventdisplacement of the swivel seal 244, there is provided an externallysecured plate 248.

The fulcrum rod 240 is biased into the counterclockwise position, asshown in FIGURE 2, by a compression spring 250 mounted within a bore 251of lug 236 and secured onto the outwardly extending portion of rod 240.The innermost end 252 of rod 240 contacts pin 220 so that the spring 250biases the valve body 214 upwardly with the lip 216 in sealing contactwith downwardly tapering valve seat 212. The wei ht of the valve body214 holds the pin 220 in contact with rod end 252 and the valve body canrotate less than 90 degrees because the lugs 222 extend downwardly agreater distance than pin 220.

In operation of the valve 210, the spring 250 holds the valve closedwhen the solenoid 232 is not actuated. In this position, water from sump52 flows into recycling passageway 90 and is forced by pump 160 upwardlythrough the perforated jet tower 40. With the motor still rotating inthe same direction, the solenoid 23-2 is actuated to terminate therecycling stage and initiate the drain stage of the mechanism 56. Withthe solenoid 232 actuated, the rod 240 is pivoted in a clockwisedirection as shown in FIGURE 2 so that the weight of valve body 214opens the valve 210 to allow the water from sump 52 to pass through therecycling passageway 93 into the drain passageway 92 where it can beforced through drain line 44 by drain pump 16%. Radially extending ribs254 on valve body 214, best shown in FIGURE 3, are used to guide themovement of the valve body 214 within opening 211 as the rod shifts thevalve 210 between the opened and the closed positions. The outwardlytapering valve seat 212 acts as a self-flushing arrangement for valve210. Any large particles which enter the opening 211 will be flushedfrom true valve seat by the flow of water through opening 211.

From this description of the operation of valve 210, it is appreciatedthat the only control for selectively changing the cycle stage ofcirculating mechanism 50 is the actuation of valve 210. With the valveclosed, the mechanism actuates to recycle water through the cabinet 16and with the valve open, the mechanism 50 operates to drain the waterfrom the cabinet. Such a construction greatly simplifies the control ofthe water circulating mechanism and, thus, reduces the manufacturingexpense and the subsequent maintenance cost while using the mechanismfor a prolonged period in a dishwasher.

In accordance with another aspect of the present invention, the valvebody 214 is provided with an upwardly extending stand pipe 269 having acentral opening 262 communciated directly with the drain passageway 92.The stand pipe extends through an opening in screen 76, not shown, andinto a cabinet 16 adjacent wall 16. A plurality of apertures 264 in theuppermost end of the stand pipe act as an overflow control for thecabinet 10. The apertures maintain a maximum water level 266 within thecabinet 10, as is best shown in FIGURE 1. If the water level Within thecabinet tends to exceed the level 266, the water is drained throughopening 262 into the drain passageway 92 where it is forced by pumpthrough the drain line 44.

During the drain stage of mechanism 50, the valve 210 is opened so thatwater is pumped from sump 52 out line 44; however, the pump 160 actsagainst a certain pressure head created within line 44. When the motor128 is turned 011?, the pressure head forces water from line 44 backinto the passageway 92. In accordance with the present invention, thevolume of passageway 92 is so selected that it can generally handle thewater forced back into the mechanism 50 by the pressure head on line 44;however, in some instances, the volume of water being forced back intothe mechanism may exceed the volume of passageway 92. The excess Watertends to increase the seal force between lip 216 and surface 212 sovalve 210 acts as a backwash valve. In addition, the excess Waterprogresses upwardly into opening 262 of the stand pipe 26%. If it werenot for the additional volume allowed by the stand pipe 266, the excesswater Within the drain passageway 92 could possibly be forced throughseal 199 into the recycling passageway 96. If this should happen, thepump 1% would circulate stagnant water through the cabinet 10 during thenext recycling stage of mechanism 50. This would tend to stain thedishes being washed. Consequently, the provision of the stand pipe 26%serves the dual function of limiting the water level within the cabinet16 and preventing the accumulation of stagnant water in the recyclingsystem of the mechanism 50.

Various other structural features of the water circulating mechanism 50enhance its general operating characteristics. For instance, a pluralityof arcuately positioned posts 279, as shown in FIGURES 2, 3 and 4, guardthe axial inlet 166 of pump 160 from large items such as pits, particlesoif dishes, etc. Such large items can accumulate in the bottom ofpassageway 92 for a prolonged time '2 without seriously affecting theoperation of the mechanism Sit.

Another structural feature of importance is the provision of a pluralityof longitudinally extending reinforcing ribs 280 in passageway 90 whichribs are not only reinforce the partition 86 but also substantiallydecrease the turbulence of water flowing longitudinally through therecycling passageway. Thus, the water received by the pump has somewhatlaminar flow in the passageway 99. The partition 86 is provided withdownwardly extending ribs 299 similar to ribs 280 in the recyclingpassageway 90. These ribs 290 are in the upper portion of the drainpassageway; therefore, they have a somewhat lesser effect on the flow ofwater in drain passageway 92.

The assembly of the mechanism as shown in the drawings is quite simple.First, the housing is assembled by bonding the portions 82, 84 togetherwith partition 86 secured therebetween. Thereafter, the seal 190 ispositioned over shaft 174 and the impeller 170 is dropped into thechamber 164. Then, the lock ring 200 is forced into partition 85. Inthis manner, seal 190 is secured in place and the insert 182 determinesthe vertical position of impeller 170. The ring 112 is then bolted overopening and impeller is mounted onto shaft of motor 128. The post 179 isthereafter slipped over extension shaft 176 so that the impel lers 120and 170 are drivingly secured together onto motor shaft 125. The pumps100, 160 are assembled by bolting housing 192 onto housing 80.

The actuator 23% is assembled onto lug 236 with the rod end 252extending below opening 211 in partition 86. Thereafter, the stand pipe260 is forced through the opening 211 so that the rod end 252 contactspin 220, as is shown in FIGURE 2. This completes the assembly ofmechanism 5!} so that it can then be attached to wall 16.

In general operation, the motor 128 is started by a relay to commencethe washing cycle. Thereafter, valve 32 directs water into cabinet 10through pipe 30. This water is circulated through the perforated jettower 40 to impinge upon the dishes on racks 22, 24. The water thenaccumulates in sump 52 where it is recycled through passageway 90 bypump 100. This operation is terminated by a timing device (not shown)after the dishes have been thoroughly washed. Thereafter the solenoid232 is actuated which opens valve 210 so that the water is pumped fromsump 52 out line 44 by pump 160.

After a preset time interval, the solenoid is again deactuated whichallows spring 250 to close valve 210.

Then again, water is directed into the cabinet 10 by pipe 30 so that therinsing cycle can be-accomplished. The rinsing cycle is basically thesame as the previously described recycling operation which was used towash the dishes within the racks 22, 24 except no detergent or cle aningsubstance is used. After the rinsing cycle has been timed out, thesolenoid 232 is again actuated to open valve 210 so that the rinse waterwithin the sump 52 can be drained through line 44.

It is noted that control of mechanism 50 requires only the actuation ofsolenoid 232 to shift from the recycling stage of the mechanism to thedrain stage. Such a control can be easily accomplished by a veryinexpensive and durable timing device. The motor 128 is continuouslyrotating in the same direction during the complete operation ofmechanism 50; therefore, there is no necessity for changing the speed ordirection of rotation of the motor.

The present invention has been described in connection with a particularstructural embodiment which has proven satisfactory in use; however, itis appreciated that the structural embodiment may be modified withoutdeparting from the intended spirit and scope of the present invention asdefined in the appended claims.

Having thus described our invention, we claim: 1. A water circulatingmechanism for a washing unit having a cabinet, a water spray device insald cabinet and a lower sump in said cabinet, said mechanism comprising a single, non-reversible motor, a recycling passagewaycommunicated with said spray device, a drain passageway communicated toa drain outlet, a first impeller for circulating water through saidrecycling passageway, and a second impeller for exhausting water fromsaid drain passageway, both of said impellers driven by said singlemotor, one passageway being vertically lower than the other, said higherpassageway being communivalve means includes a valve body and a standpipe carried by said body to allow for excessive water drain back insaid drain passageway.

5. A mechanism as defined in claim 2 wherein said drain passageway has avolume generally equal to or exceeding the volume of said water forcedback into the mechanism through said drain outlet when'said motor isde-energized.

6. A mechanism as defined in claim 2 wherein said drain passageway has astand pipe to allow for excessive water drain back in said drainpassageway.

7. A mechanism as defined in claim 6 wherein said stand pipe extendsinto said sump.

8. A mechanism as defined in claim 7 wherein said stand pipe has anupper opening to provide an overflow communicating said sump with saiddrain at all times.

9. In a dishwasher water circulating mechanism comprising a cabinethaving a lower sump, a recycling passageway communicated with said sump,a drain passageway, a valve means for selectively connecting said drainpassageway with said sump, impeller means in said recycling passagewayfor pumping water from said recycling passageway into said cabinet, andimpeller means in said drain passageway for exhausing water from saidsump when said valve means is opened, the improvement comprising: saidrecycling passageway being directly below said sump, said drainpassageway being directly below said recycling passageway and said valvemeans being positioned between said passageways whereby water will flowinto'and through said recycling passageway when said valve is closed andwill by-pass said recycling passageway and flow into said rainpassageway when said valve is opened.

10. The improvement as defined in claim 9 wherein said valve meansincludes an aperture between said passageways, a valve seat around theperiphery of said aperture, a peripheral valve element to selectivelycontact said valve seat to seal said drain passageway from saidrecycling passageway and a stand pipe extending upwardly into said sump,said stand pipe communicating said drain passageway with said sump andforming an overflow control in said sump.

11. The improvement as defined in claim 10 wherein said drain passagewayhas a volume generally equal to or exceeding the volume of water forcedback into the mechanism when said motor is de-energized.

12. A water circulating mechanism for a washing unit having a cabinet, awater spray device in said cabinet and a lower sump in said cabinet,said mechanism comprising a single housing, a recycling passageway inthe upper part of said housing and communicating said sump with saiddevice, a drain passageway in the lower part of said housing andcommunicated to a drain outlet, said passageways being generallycoextensive in said housing, a pumping chamber in both of saidpassageways, said chambers being generally aligned in a verticaldirection, an impeller in each of said pumping chambers for circulatingwater in the respective passageways, a single, non-reversible motorabove said pumping chambers and secured to said housing, said motorhaving a single shaft for driving both of said impellers simultaneously,an opening communicating said passageways and remote from said pumpingchambers, and a valve means for selectively closing said opening tocontrol the operation of said mechanism while said motor is energized todrive said impellers.

13. A mechanism as defined in claim 12 wherein said drain passageway hasa stand pipe extending into said 10 sump with an upper opening toprovide an overflow communicating said sump with said drain passagewayat all times.

References Cited by the Examiner UNITED STATES PATENTS M. CARY NELSON,Primary Examiner.

W. R. CLINE, Assistant Examiner.

9. IN A DISHWASHER WATER CIRCULATING MECHANISM COMPRISING A CABINETHAVING A LOWER SUMP, A RECYCLING PASSAGEWAY COMMUNICATED WITH SAID SUMP,A DRAIN PASSAGEWAY, A VALVE MEANS FOR SELECTIVELY CONNECTING SAID DRAINPASSAGEWAY WITH SAID SUMP, IMPELLER MEANS IN SAID RECYCLING PASSAGEWAYFOR PUMPING WATER FROM SAID RECYCLING PASSAGEWAY INTO SAID CABINET, ANDIMPELLER MEANS IN SAID DRAIN PASSAGEWAY FOR EXHAUSING WATER FROM SAIDSUMP WHEN SAID VALVE MEANS IS OPENED, THE IMPROVEMENT COMPRISING: SAIDRECYCLING PASSAGEWAY BEING DIRECTLY BELOW SAID SUMP, SAID DRAINPASSAGEWAY BEING DIRECTLY BELOW SAID RECYCLING PASSAGEWAY AND SAID VALVEMEANS BEING POSITIONED BETWEEN SAID PASSAGEWAYS WHEREBY WATER WILL FLOWINTO AND THROUGH SAID RECYCLING PASSAGEWAY WHEN SAID VALVE IS CLOSED ANDWILL BY-PASS SAID RECYCLING PASSAGEWAY AND FLOW INTO SAID RAINPASSAGEWAY WHEN SAID VALVE IS OPENED.